In the area of veterinary medicine, there are certain oral procedures which require the patient's mouth to be securely held in the open position for what may often be extended periods of time. Such procedures typically include the oral examination and routine dental treatment of the patient's mouth and teeth. Such procedures can also include the initiation and maintenance of general anesthesia intubation which is incidental to the performance of other surgical procedures. During the performance of any of these procedures it is necessary to protect the veterinarian's hands, the uncompleted dental work, the breathing tube and even the patient itself from sudden and unexpected mouth closure. And it is often necessary to provide such protection for extended periods of time.
The use of mouth props is well known in the area of human dentistry. See, for example, U.S. Pat. No. 2,220,674 issued to Bloomheart and U.S. Pat. No. 4,887,965 issued to Fox. Although such devices may be adaptable for use, on a different scale or size, with herbivore veterinary patients, the structural differences which exist between human jaws and teeth and that of their carnivore counterparts limit the usefulness and application of such devices in that area of veterinary medicine. This is not to say, however, that other devices do not exist for such application.
The use of devices for holding an animal's mouth open is also well known. The most common device currently available is similar in structure to the device shown and disclosed in U.S. Pat. No. 2,019,060 issued to Thibert. It consists of a configuration of three metal bars. A central bar is provided along which are situated two slidably movable and generally perpendicularly extending support bars. The central bar is encircled by a spiral spring which holds the support bars apart. The support bars are slidably adjustable along the length of the central bar so as to provide a wide variety of distances or settings for accommodating a variety of animal mouth sizes. The sliding support bars are fitted with rubber or nylon grommets which engage the animal's teeth.
In the experience of the applicant, numerous problems have been known to develop when such devices are used. In addition to being cumbersome and unwieldy, such devices often lend themselves to uncertain and uneven spring tensions and interference with tooth surface exposure. With the advent of the performance of more sophisticated and complex veterinary dental procedures such as root canals, pulp capping and restoration and surgery of the gums and jaw, maximum mouth and tooth surface exposure is necessary. The use of such a device often impedes or blocks access to such mouth and tooth exposure.
Another major complication caused by the metal devices is that they lack radiolucency. They must often be moved or removed in order for dental x-rays to be taken.
Additionally, rubber gloves and facial fur are frequently pinched and caught in the spiral spring between the sliding support bars. It is not uncommon for there to be a degeneration of the rubber or nylon grommets. The grommets may break or become worn and work out of position. With the grommets either missing or misaligned, teeth may be lodged directly against metal which can lead to tooth injury and failure of the device altogether. These metal devices do not lend themselves to quick and easy clean up once the veterinary procedure is completed.